In many tropical and semi-tropical regions, it is important to identify horses having inadequate thermal regulatory responses to hot, humid climates ("anhidrotic horses"). Anhidrosis is the incapacity of horses or other animals to perspire in response to adequate stimulation. It affects horses of any age, race or color. Though it has been reported that horses with rigorous training for racing, polo or jumping, or with highly concentrated diets, are more susceptible, recent studies show that mother mares and inactive horses get sick with the same frequency. Anhidrosis was first described by T. W. Wright and T. C. Tull in Vet. J. 81: 235-239 (1925), incorporated herein by reference. Such anhidrotic horses are not able to work or exercise strenuously because of their inability to adequately dissipate body heat in such climates, since sweating is the primary mechanism for heat dissipation in horses. This topic was discussed by Correa and Calderin in the Journal of the American Veterinary Medicine Association (J.A.V.M.A.), Anhydrosis, Dry-Coat Sundrome in the Thoroughbred, Vol. 149, December 1966, pp. 1556-1560, incorporated herein by reference. A number of possible causes of equine anhidrosis have been considered, but none have been established; therefore treatment has been empirical.
According to Arthur C. Guyton in Textbook of Medical Physiology, Chap. 73, (1992), when reference is made to different forms of heat loss, it involves irradiation, conduction and evaporation, it being indicated that 22% of heat is lost through evaporation, and that if adequate evaporation is prevented for any reason when the ambient temperature is greater than the body temperature, it will allow the body temperature to rise. There exists a temperature control system that utilizes three major mechanisms to reduce body heat when temperature increases excessively: (1) vasodilatation, (2) sweating, and (3) decreased heat production. When there is no sweating, there cannot be evaporation and such 22% heat loss would not exist. Hence, that heat would remain in the body.
Equine anhidrosis, first reported in British thoroughbreds taken to tropical colonies early in this century, is also known as "non-sweating", "dry-coat syndrome", "blowing" or "puff disease", and is manifested by ineffective sweating in response to appropriate stimuli. Sweat evaporation is the primary cooling mechanism for horses when the ambient temperature exceeds the body temperature. Anhidrotic horses have compromised thermoregulatory function and are in great danger of hyperthermia. Normal equine rectal temperature is about 99.5-101.5.degree. F.; if asked to perform at extremely high ambient temperatures, anhidrotic horses have been known to achieve rectal temperatures of 108.degree. F. and may collapse and die if raced. Providing shade or decreasing activity gives these horses only minimal relief.
Clinical features, pathogenesis and background of equine anhidrosis are described in U.S. Pat. No. 5,276,056 to LeRoy, incorporated herein by reference. The signs most commonly observed at the onset of anhidrosis are rapid breathing (tachypnea), the most common sign reported, fatigue, low tolerance to exercise and hair loss, especially in the face. Occasionally there is a slight loss of appetite, changes in water consumption and loss of general health. The commencement of the affliction usually starts during spring and summer, and can be abrupt or gradual. Many horses will maintain sweating under their manes and above their chests, with little or none produced in the rear. Partial anhidrosis can resolve itself in the winter, where apparently normal perspiration occurs.
Diagnosis of anhidrosis is based on small amounts of sweating produced during adequate stimulation. The affected horses heave, displaying rapid breathing during warm seasons. The rectal temperature could be highly elevated. In anhidrotic horses, there are not remarkable changes in the horse's hematology, electrolytes and enzymes, nor do skin biopsies allow for diagnosis. However, inadequate glandular response can be confirmed by administering intravenous epinephrine. See article by Warner, "Anhidrosis", Current Therapy in Equine Medicine 2, W. B. Saunders Company, 1987.
While the pathogenesis of anhidrosis is not known for certain, it has been suggested that its cause is a low regulation of the Beta-2 receptors of the sweat glands in response to abnormal concentration of highly circulating epinephrine, secondary to stress from heat. It is also possible that the process of secretion of the sweat glands will become fatigued after a prolonged demand. Certain characteristics of anhidrosis, such as dry skin, hair loss and decreased tolerance to exercise in heat, have led to the suggestion that hyperthyroidism is a contributing factor. However, there does not appear to be available evidence to confirm this suggestion.
Experiments in animals, whether large or small, have been conducted on a regular basis. In homeopathy, experiments can only be conducted in apparently healthy humans. In the book entitled Pure Medical Matter, Vol. 11, pp. 610-611, (reprint, 1980), Samuel Hahnemann describes anhidrosis-related experiments he conducted on humans. He conducted these experiments on humans because humans can better express the symptoms felt, and he carried them out on apparently healthy subjects. Being healthy, they showed no signs of any unbalance, that is, of any disease, and these subjects were capable of being objective and of describing the symptoms brought about by the experimental medication. The medication under study was administered to the subjects by giving repeated dosages three time daily. With the intake of repeated dosages of the medication, the bodies of the subjects had to produce an artificial disease caused by the experimental medication.
Symptoms related to skin, sweating and hair were among the many symptoms reported by the subjects. For example, the subjects reported falling out of the hair, especially on the head; complete anorexia; skin cracks here and there, especially in the open air; and scales and pruritus. More symptoms were also reported in The Guiding Symptoms of C. Hering, M.D., Vol. 10, pp. 96-193.
In this case, all of the experience gathered with humans was used to treat horses. Anhidrotic horses have been treated with various formulations with varying degrees of effectiveness. Various empirical treatments have been attempted to induce sweat in affected horses, with poor and varied results. These treatments include intravenous and oral administration of electrolytes and vitamin E. There have been efforts to provide horses with cold or at least cooler environments, by using fans or giving shade to the horse. Some have shaved the horses' bodies and moistened the bodies with water to provoke temperature loss through evaporation. Some exercise their horses during the cooler hours of the day.
One possible solution to this problem is to provide an oral composition to an anhidrotic horse which is effective in reducing the symptoms and illness associated with anhidrosis.
Another possible solution to this problem is to provide a treatment for anhidrosis which does not limit the climates or times of day when a horse can exercise and/or race.
Another possible solution to this problem is to provide a treatment for anhidrosis which does not require injections or shaving of a horse's body.
Thus, there has been a need in the art for an oral composition to an anhidrotic horse which is effective in reducing the symptoms and illness associated with anhidrosis.
There has been an additional need in the art for a treatment for anhidrosis which does not limit the climates or times of day when a horse can exercise and/or race.
There is yet another need in the art for a treatment for anhidrosis which does not require injections or shaving of a horse's body.